Photon Phase Shift at the Few-Photon Level and Optical Switching by a Quantum Dot in a Microcavity

Wells, LM; Kalliakos, Sokratis; Villa, Bruno; Ellis, D. J. P.; Stevenson, R. M.; Bennett, A. J.; Farrer, I.; Ritchie, D. A.; Shields, A. J.

doi:10.1103/physrevapplied.11.061001

“…The crucial advantage of this technique is that it only requires optical interactions, which are intrinsically much faster than hyperfine interactions. Progress in the experimental realization of strong spin-dependent phase shifts has been made recently [23,[80][81][82]. The second condition (ii) will also be easier to achieve if the CZ gate time is reduced.…”

Section: Discussionmentioning

confidence: 99%

Resource requirements for efficient quantum communication using all-photonic graph states generated from a few matter qubits

Hilaire

¹

,

Barnes

²

,

Economou

³

2021

Quantum

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Quantum communication technologies show great promise for applications ranging from the secure transmission of secret messages to distributed quantum computing. Due to fiber losses, long-distance quantum communication requires the use of quantum repeaters, for which there exist quantum memory-based schemes and all-photonic schemes. While all-photonic approaches based on graph states generated from linear optics avoid coherence time issues associated with memories, they outperform repeater-less protocols only at the expense of a prohibitively large overhead in resources. Here, we consider using matter qubits to produce the photonic graph states and analyze in detail the trade-off between resources and performance, as characterized by the achievable secret key rate per matter qubit. We show that fast two-qubit entangling gates between matter qubits and high photon collection and detection efficiencies are the main ingredients needed for the all-photonic protocol to outperform both repeater-less and memory-based schemes.

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“…The crucial advantage of this technique is that it only requires optical interactions, which are intrinsically much faster than hyperfine interactions. Progress in the experimental realization of strong spin-dependent phase shifts has been made recently [23,[71][72][73]. The second condition (ii) will also be easier to achieve if the CZ gate time is reduced.…”

Section: Discussionmentioning

confidence: 99%

Resource requirements for efficient quantum communication using all-photonic graph states generated from a few matter qubits

Hilaire,

Barnes,

Economou

2020

Preprint

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Quantum communication technologiesshow great promise for applications ranging from the secure transmission of secret messages to distributed quantum computing. Due to fiber losses, long-distance quantum communication requires the use of quantum repeaters, for which there exist quantum memory-based schemes and all-photonic schemes. While all-photonic approaches based on graph states generated from linear optics avoid coherence time issues associated with memories, they outperform repeater-less protocols only at the expense of a prohibitively large overhead in resources. Here, we consider using matter qubits to produce the photonic graph states and analyze in detail the trade-off between resources and performance, as characterized by the achievable secret key rate per matter qubit.We show that fast two-qubit entangling gates between matter qubits and high photon collection and detection efficiencies are the main ingredients needed for the all-photonic protocol to outperform both repeater-less and memory-based schemes.The ability to share entangled states over long distances is a major milestone for the realization of a fully-functional quantum internet [1,2]. Beyond secure communications via Quantum Key Distribution (QKD) [3][4][5], the implementation of such a quantum internet would also have various applications ranging from distributed quantum computing [6], secure access to a remote quantum computer [7,8], accurate clock synchronization [9], and improved telescope observations [10].

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“…Given access to such CZ gates, photonic graph states can be generated on demand via timedelayed feedback [41]. In experiments, the phase angle on photonic qubits induced by the nonlinearity from the cavity-QED system is not yet fully controllable [38,[42][43][44][45][46]. Instead of a CZ gate, the gate that is applied to the photonic qubits is a controlled-phase (CP) gate [47][48][49][50].…”

Section: Introductionmentioning

confidence: 99%

Extracting perfect GHZ states from imperfect weighted graph states via entanglement concentration

Rafail¹,

Liu²,

Raissi³

et al. 2022

Preprint

0

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Photonic GHZ states serve as the central resource for a number of important applications in quantum information science, including secret sharing, sensing, and fusion-based quantum computing. The use of photon-emitter entangling gates is a promising approach to creating these states that sidesteps many of the difficulties associated with intrinsically probabilistic methods based on linear optics. However, the efficient creation of high-fidelity GHZ states of many photons remains an outstanding challenge due to both coherent and incoherent errors during the generation process. Here, we propose an entanglement concentration protocol that is capable of generating perfect GHZ states using only local gates and measurements on imperfect weighted graph states. We show that our protocol is both efficient and robust to incoherent noise errors.

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Photon Phase Shift at the Few-Photon Level and Optical Switching by a Quantum Dot in a Microcavity

Cited by 17 publications

References 44 publications

Resource requirements for efficient quantum communication using all-photonic graph states generated from a few matter qubits

Resource requirements for efficient quantum communication using all-photonic graph states generated from a few matter qubits

Resource requirements for efficient quantum communication using all-photonic graph states generated from a few matter qubits

Extracting perfect GHZ states from imperfect weighted graph states via entanglement concentration

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